1. Field of the Invention
Processing of fish for the recovery of fish eggs or for filleting has in the past required much handwork and has been wasteful of labor and fish. To harvest fish eggs all of the fish in a batch have been processed indiscriminately, although less than half of the fish have yielded any substantial quantity of eggs because male fish do not produce eggs, and eggs in some females may be too immature for the desired use.
In a fish-filleting operation, it may be uneconomical to fillet a fish of less than a predetermined size. Also, in order to accomplish the most effective fish-filleting operation, it is desirable for the fish to be oriented with its back at one predetermined side and its belly at the opposite side.
The present invention provides an apparatus and method for orienting and sorting fish automatically in accordance with particular characteristics to facilitate processing of the fish for a particular purpose.
If eggs are to be harvested from fish, the apparatus and method of the present invention can be utilized to sort the fish according to their sex. A female fish containing eggs is much more transparent than a male fish. Consequently, utilization is made of the transparency characteristic of such fish as a basis for simply determining their sex or actually to sort the fish into two classifications, male and female. As used in the following description "transparent" refers to the ability to transmit radiant energy whether or not such energy is visible light, and "opaque" refers to the substantial inability to transmit radiant energy.
Alternatively, for filleting purposes, for example, fish can be sorted into classifications, one class of which contains only fish of a sufficient size to be filleted effectively and oriented so that the back of each fish faces in a predetermined direction. The other class would include fish not of a proper size or not properly oriented for filleting.
2. Prior Art
Prior patents pertaining to the sorting of herring as to sex are Norwegian Pat. No. 90487, entitled Method for Sorting Herring and Fish and Apparatus for Carrying Out the Method, issued Nov. 25, 1957, and Cuthbert U.S. Pat. No. 3,859,522, for Method for Nondestructive Testing of Fish for Sex.